Eraser mounting for pencils



Aug. 26, 1958 v w. scHFER 2,848,978

ERASER MOUNTING FOR PENCILS Filed Nov. '7, 1955 Patented Aug. 26, 1958.Cree

ERASER MoUNrING Fon PENCILS Wilhelm Schfer, Numberg, Germany, assignorto A. W.

Faber-Castell, Stein near Numberg, Germany, a German firm ApplicationNovember 7, 1955, Serial No. 545,484

Claims priority, application Germany November 26, 1954 6 Claims. (Cl.1Z0- 38) The present invention relates to new improvements in erasermountings for pencils.

For convenience in making corrections it has been known for a longtimeto provide one end of pencils With a small eraser which usually wassecured thereto by means of a socket, preferably of metal, which wastted to the pencil so that the rubber eraser formed an extensionthereof. one end of the latter was usually milled olf or otherwisereduced in diameter so as to form a short cylindrical portion upon whichthe socket was fitted and then secured by punch marks. Although thistype of eraser mounting was very inexpensive, it had the annoyingdisadvantage that, when using the eraser, the connecting socket wouldeasily come loose from the pencil. At first it would wiggle when beingused and eventually come oif the pencil entirely. On the other hand,when using sockets of plastic material, this manner of mounting them onthe pencils by means of punch marks could not be used at all, andtherefore attempts were made to secure the plastic socket by means of anadhesive cement. However, it was found that because of the necessarywall thickness of the plastic socket and the fact that in fitting thesocket on the pencil the cement was partly squeezed out, the pencilbecame both clumsy and ugly. The result was a considerable reduction incustomer appeal and a loss in sales value of the pencils.

In order to prevent the excessive amount of cement, it has beensuggested to supply it by means of a pump. Although this usuallyprevented the cement from emerging from the socket, it still did notresult in a neat and secure connection.

It is the object of the present invention to overcome thesedisadvantages of the prior art and to provide a neat and secureconnection of the eraser socket on the pencil by providing at least oneof the connecting parts, that is, either the wooden end of the pencil orthe socket, or both, with suitable depressions `or grooves for taking upand retaining the cement therein, thus permitting an adequate amount ofsuch cement to be supplied to the connecting surfaces to insure a secureconnection, and preventing the cement from emerging from the socket.

A feature of the invention consists in the provision of such grooves inthe form of interconnected channels extending in a direction eitherlongitudinally or transverse of the pencil or in both directions. Thesechannels will insure a proper distribution of the cement over theconnecting surfaces of both pencil and socket and thus a secure and neatconnection of the socket on the pencil.

Another feature of the invention applicable to pencils of polygonalcross section consists in partly removing the anguler edges thereof andin applying the longitudinal channels between the surfaces intermediatesuch edges and the inner wall of the socket which is thereafter attachedthereto. This will render a separate insertion of channels into the woodofthe pencil unnecessary.

Another preferred feature of the invention resides in providingtransverse channels within the socket, prefer For securing the erasersocket to the pencil,

ably by molding circular grooves into the cylindrical surface thereof.The stability of the connection may be further increased according tothe invention by making the inner diameter of the socket and thediameter between two diagonally opposite broken edges of the pencil endof equal size so that, when connected, the socket will be in directengagement with the pencil along these broken edges.

Another object of the invention is to provide a method and suitablemeans for injecting the cement into the channels of the two connectingparts after the same have been attached to each other. For this purpose,the invention provides a suitable pump which permits the injection intothe channels of just the proper quantity of cement required and which ispreferably provided with an annular groove immediately adjacent and infront of the nozzle end thereof which forms a constriction of the nozzleand allows an easier and cleaner separation of the cement therefrom sothat the proper amount of cement may thus be supplied.

Another feature of the invention consists in the use of a cement in theform of an adhesive of viscous, readily applicable consistency,preferably a watery dispersion of polyvinyl acetate as commonly used asa synthetic adhesive for gluing Wood. After being inserted into thechannels, the viscosity of such a cement prevents the same from runningout of its own accord, and insures its uniform distribution within thechannels.

Such rdistribution of the cement within the channels after the same hasbeen applied by means of the pump is preferably carried out according tothe invention by forcing the rubber eraser into the socket on thepencil. The eraser then functions in the socket like a piston sliding ina cylinder and compresses the cement into the channels. The smallresidue remaining between the contacting surfaces after the eraser hasbeen inserted also secures the latter within the socket to the end ofthe pencil. The accurate dosage of cement supplied by the pump insuresthat all channels will be completely filled and that no cement willemerge at the socket ends.

Further objects, features, and advantages of the present invention willappear from the following detailed description thereof which is to beread with reference to the accompanying drawings, in which j Fig. lshows a plan view of an eraser mounted on a pencil by means of a socketaccording to the invention;

Fig. 2 shows a plan view of the end of a pencil, the projecting cornersof which have been partly milled oif;

Fig. 3 shows a central longitudinal section through a pencil with asocket attached thereto;

Fig. 4 shows a similar section through a pencil with a socket attachedthereto and a cement pump inserted into the socket;

Fig. 5 shows a cross section taken along line V-V of Fig'. 2;

Fig. 6 shows a cross section taken along line VI-VI of Fig. l;

Fig. 7 shows a cross section taken along line VII-VII of Fig. l; whileFig. 8 shows a cross section taken along line VIII-VIII of Fig. l.

Referring to the drawings, and first to Figs. l to 5, the projectingcorners of one end or terminal of a pencil l of the customary hexagonalcross section and containing a lead 1' are partly milled off to provideouter surfaces 3. A socket or ferrule 4 for securing the eraser 2 to thepencil 1 is slid over the milled surfaces 3 which are substantiallycircular and serve as seating surfaces for the socket. The gaps whichare then formed between the socket 4 and the surfaces 5 remainingintermediate the partly milled-off seating surfaces 3 form thelongitudinal channels 6 which are interconnected by transverse Vchannels7 provided in the seating surfaces of the rsocket 4, the latter seatingsurfaces tightly engaging the seating surfaces 3 on the terminal of thepencil.

After sliding the socket 4 to the inner end of the milled :surfaces 3,as shown in Fig. 3, the nozzle 9 of a Vcement pump 8 is inserted intothe open end of socket 4, and a certain quantity of cement 10 isinjected therein and against the blunt end or front side 11 of thepencil 1. Nozzle 9 has an annular groove 13 immediately adjascent thenozzle end 12 which facilitates the separation of the cement from nozzle9. When the tightly fitting eraser 2 is then pushed into the open end ofsocket 4, it will act like a piston sliding in a cylinder and force thecement 10 through the longitudinal channels 6 in the direction towardthe inner end of the milled portion 3 and at the same time into thetransverse channels 7 which are communicating with the longitudinalchannels 6. The quantity 10 of cement as originally applied by the pump8 on the blunt end of the pencil accurately complies with that needed toll the longitudinal and transverse channels 6 and 7 without danger thatany cement will be forced out of the socket end 14. The thin layer ofcement finally remaining on the blunt end or front side of pencil 1 aswell as the cement which has passed into the transverse channel 16adjacent to the inner end or front .side of eraser 2 rmly secures thesame to the pencil both at such end as well las along its peripheralsurface.

Figs. 6 to 8 illustrate the pencil 1 with the socket 4 'enclosing thesame. As previously mentioned, the sur- 'faces 3 are formed by millingoff a part of the projecting corners 17. The cement injected anddistributed within the longitudinal and transverse channels 6 and 7 llsout these channels completely and, after hardening, forms a solid andsecure connection between the eraser 2 and the pencil 1.

Although my invention has been illustrated and described with referenceto the preferred embodiments thereof, I wish to have it understood thatit is in no way limited to the details of such embodiments or to thespecific examples described, but is capable of numerous modificationswithin the scope of the appended claims.

Having thus fully disclosed my invention, what I claim is:

1. A pencil having a ferrule partially sleeved over to seat on one ofthe terminals of said pencil, said ferrule partially extending from saidpencil terminal and being provided with an opening at its free end, arubber eraser inserted in said opening and held in that part of saidferrule, at least one of the interengaging seating surfaces of saidferrule and said terminal having longitudinal and the other of saidsurfaces having transverse channels, said longitudinal and saidtransverse channels yrespectively intersecting one another, and a cementfilling said channels to rmly secure said ferrule to said pencilterminal at the points of intersection.

2. A pencil as set forth in claim l, said transverse channels being inthe interior surface of said ferrule and said longitudinal channelsbeing in the exterior surface of said terminal.

3. A pencil as set forth in claim 1, said pencil having polygonal shape,the edges'of the polygonal surface of said pencil being partiallyremoved at said terminal to provide said channels between an otherwisesubstantially circular seating surface for said ferrule.

4. A pencil as set forth in claim 3, said terminal having asubstantially circular cross section except for the at edges left fromthe original polygonal shape, the exterior diameter of said circularsection being substantially the same as that of the interior diameter ofsaid ferrule.

5. A pencil as set forth in claim 1, the diameter of said terminal beingslightly smaller than the largest dimension of the cross section throughthe other part of said pencil.

6. A pencil as set forth in claim l, wherein said cement comprises aviscous mass capable of hardening land substantially lling the spacewithin said ferrule intermediate adjacent front sides of said pencilterminal and said eraser to join said front sides to one another 'and tosaid ferrule.

References Cited in the le of this patent UNITED STATES PATENTS 457,579Faber Aug. 11, 1891 2,180,132 Zoll Nov. 14, 1939 2,444,997 Lovesey July13, 1948 2,568,274 Clark Sept. 18, 1951 2,785,100 Yaw Mar. 12, 1957

